Insulated concrete form (ICF) construction techniques typically involve fixing two foam forms a fixed distance apart and pouring concrete between the forms. After the concrete has set, the foam forms remain in place to provide insulation for the concrete structure. Reinforcing members, such as rebar or mesh, may be located in the gap between the forms before the pour to become embedded in the concrete and provide reinforcement to the structure after the concrete sets.
Depending upon the application, the foam forms may require additional support to ensure their alignment is maintained during the pour since the concrete is considerably heavier than the foam forms and the bottom of the forms experiences a hydrostatic force imparted by the total height of concrete poured. Supporting the foam forms in some fashion is often required to prevent the concrete from forcing the forms out of alignment resulting in misaligned structures or surfaces of the structures that don't follow the intended surface line of the foam forms.
Foam forms for ICF construction typically have ties that hold the two foam layers a set distance apart during the concrete pour. An example of a suitable foam form are Nudura (trade-mark) forms, though other suitable forms are also commercially available comprising a high enough density and appropriate chemical formula to meet the fire requirements. While the present application only illustrates straight foam forms for straight walls comprising two planar rectangular foam layers for ease of illustration, forms for alternate wall configurations including angles, corners and curves may also similarly be used.
Multi-storey concrete structures have traditionally not been constructed using ICF due to the difficulties in maintaining alignment of the forms during the pour. While ICF is used for construction near ground level, inaccuracies in alignment tend to become exaggerated with each additional storey of construction making their use in multi-storey structures more problematic. Deviations in the forms during the pour require repairs to the foam and concrete structure that are difficult, time consuming and expensive.
One aspect of the difficulties faced in building multi-storey concrete structures using ICF construction techniques has been the lack of ready access to the outside of the structure during construction above the first storey. Another aspect of the difficulties faced in building multi-storey concrete structures using ICF construction techniques has been the difficulty in anchoring and supporting the outer surface of the structure during construction above the first storey.
A method of ensuring alignment of forms at ground level during the pour has been to secure supplementary supports about the external surface of the forms to provide additional support and maintain them in alignment. At ground level supplementary supports are typically anchored to the ground. One common type of supplementary support is constructed from two sets of wooden boards with metal ties maintaining the distance between the sets of boards. Supports of this kind are relatively expensive and time-consuming to use in ICF construction for multi-storey structures.
A method of ensuring alignment of forms in multi-storey structures has been to tie the outer form into support members previously cast into set concrete. One difficulty with this method is the time taken to tie the forms into the support members. Another difficulty with this method is ensuring the outer form is sufficiently supported to withstand the pressure of a concrete pour without having the forms become misaligned.
There is a need for a system and method of ICF construction that avoids the difficulties faced with current construction techniques.
There is a further need for a system and method of ICF construction that results in each storey of an ICF structure under construction being a stable storey capable of supporting additional higher storeys for construction.